Instead of prepping your vegetables before each meal consider doing a weekly batch prep where you get all your vegetables ready for the week in an hour or less.

Fitness weblog The Four-Hour Body Couple (a fanblog based on Tim Ferriss' The Four-Hour Body) noticed how the vegetables are prepped and ready to go at sub shops and reasoned that if ready-to-use vegetables at home were as accessible as the sub shop they would consume a lot more vegetables. They started doing a once-weekly batch prepping session and putting all the sliced/chopped vegetables in tupperware containers for the week. They found that a lot of their individual prep time was spent cleaning up from chopping veggies. This cleanup time is pretty much the same whether you prep once weekly or for every individual meal.

The author at the weblog estimated that if vegetable meal prep takes 10 minutes per meal (5 minutes for chopping/slicing and 5 minutes for cleanup) for each of their four daily meals, they were spending 280 minutes on meal prep. Since their weekly batch prep only takes 40 minutes they've estimated they save four hours of time per week.

Adding a slice of tomato to a sandwich or chopped onions or peppers to your eggs in the morning often make your food tastier and healthier but when you're hungry now you may not want to peel and slice extraneous veggies or fruits. Having a ready-made stash of fresh-cut veggies makes it way more likely that you'll eat healthier and save your prep time as well.